The metal is fine on my red fastraps, but the nylon material has gotten stiff.

My older green fastraps work fine, must have been pre-treated with something.

you got nothin to lose by trying it right? made some of my ratchet straps softer than when they were new. spray emd own lightly, wipe it in and be done. it will repell moisture too. try it on one and if you don't like it get new straps, if you do like it spray the other and instead of buying new straps buy more ff